The present invention relates to a pneumatic conveying machine, and more particularly to a new and improved insulation application machine for applying mineral wool, fiberglass, and cellulose materials into building cavities, attics and the like.
In the past, not all buildings were insulated. Primarily, those buildings built in the half of the hemisphere adjacent the equator were not insulated and those buildings built in the half of the hemisphere adjacent the poles were insulated. Then came the commercialization of air conditioning and the requirement that these existing buildings all be insulated. One way to insulate an existing building is to apply insulation such as mineral wool, fiber-glass, or cellulose materials into the walls, ceilings and attic space. Various types of insulation application machines have been proposed. Typical examples of such machines are described in U.S. Pat. Nos. 3,861,599, Waggoner; 4,111,493, Sperber; and 4,560,307, Deitesfeld et al.
Most of these insulation machines have a hopper in which the fibrous material is initially placed. These hoppers have conventionally been tapered and cause bridging of the fibrous material in the hopper. Hoppers have been provided with agitators by which the packaged fibrous material is broken apart and prepared for applying through an air duct into position within a building. Between the rotary air lock and the hopper these insulation machines usually have a manually operated slide damper which provides the primary means of controlling the feed of fibrous materials into the air lock and the air conveying systems without losing air pressure through the hopper. However, the fibrous material is also known to bridge within the hopper before it gets to the air lock. Therefore, it is highly desirable to provide a new and improved automatic pneumatic conveying machine for applying insulation materials.
All known insulation machines and systems being utilized today are manually controlled. This results in widely varying material flow rates into the pneumatic conveying ducts thereby creating over-feed conditions resulting in plugging or under-feed conditions creating excessive air and dust in the application areas.
It is therefore highly desirable to provide a new and improved pneumatic conveying machine designed to apply fibrous materials to be used as insulation, packaging materials, bedding, hydro-mulching and the like into open spaces or cavity fill applications. It is also highly desirable to provide a new and improved pneumatic conveying machine having a hopper for fibrous materials that has a live bottom agitation system allowing for the use of straight vertical sides that eliminate bridging within the hopper. It is also highly desirable to provide a new and improved pneumatic conveying machine having a recirculating ribbon agitator system to decompress packaged materials that continually overflows the machine's feeder system, thereby providing a uniform rate of conditioned feed material from the hopper into the air duct.
Normally, machine operators are not skilled sufficiently to manually control the machines to prevent plugging and to maintain optimum feed conditions. Usually, to avoid plugging problems, operators set these manual machines to underfeed, thereby greatly reducing overall production, creating excess air and dust in the application area. Thus, it is highly desirable to provide a new and improved pneumatic conveying machine by which the applied consistency of the material can be better controlled. It is also highly desirable to provide a new and improved pneumatic conveying machine by which the moisture content of the insulation material in systems where dry adhesives are commingled with the fibrous materials can be better controlled. It is also highly desirable to provide a new and improved pneumatic conveying machine by which the feeding of the various materials into the pneumatic duct system can be better controlled.
In some of the prior art machines, an air lock is located between the damper system and the air duct such that fibrous material can be added to the air duct without a loss of air pressure within the duct through the hopper. As it may be necessary to apply fibrous material several hundred feet and to elevations several stories high, maintaining air pressure within the air duct is necessary. This is difficult without an efficient air lock between the hopper and the air duct. Therefore, it is highly desirable to provide a new and improved air lock for a pneumatic conveying machine. It is also highly desirable to provide a new and improved air lock in which an air seal between the hopper and the air duct is always maintained. It is further highly desirable to provide a new and improved control means by which the materials to be conveyed can be fed into the air stream at controlled rates so as to minimize or eliminate plugging in the air duct.
The inventors have discovered that the material handling capacity of a pneumatic conveying machine or system is directly related to the conveying duct diameter, conveying lift, material particle or fiber size, material density, atmospheric conditions such as temperature and humidity and the air velocity within the duct. All of these parameters impart a greater or lessor resistance to the air and material flow through the conveying ducts which can be effectively measured as system air back pressure.
In order to completely eliminate plugging of the air duct, there needs to be a way to monitor the quantity of material being fed into the air lock and a way to automatically vary the rate of feed into the conveying duct as the consistency and the properties of the feed material varies. The composition of insulation materials varies greatly by moisture content, fiber size and density within small lots. The dampers, set by hand, cannot be adjusted fast enough to eliminate dusty conditions and plugging. Therefore, it is highly desirable to provide a new and improved pneumatic conveying machine by which the amount of material fed to the conveying duct can be automatically varied as the properties of the material application conditions varies. It is also highly desirable to provide a new and improved pneumatic conveying machine which with an automatic feed control system designed to maintain a steady and maximum flow of feed stock into the pneumatic conveying duct resulting in substantially greater production rates at a given energy input without causing conveying dust or plugging. It is also highly desirable to provide a new and improved pneumatic conveying machine which has a fully automatic feed control system designed to accurately proportion the addition of water or other additives in direct ratio of the feed stock flowing into the conveying ducts. It is also highly desirable to provide a new and improved pneumatic conveying machine which has a fully automatic feed control system that is designed to automatically adjust and balance the material feed rate into the machine's handling capacity of the pneumatic conveying duct to accommodate continual and widely varying physical properties of the feed stock and application conditions such as duct length and lift as may be required in specific applications. It is also highly desirable to provide a new and improved pneumatic conveying machine that is electrically operated and driven which consumes significantly less power for given output rates. It is also highly desirable to provide a new and improved pneumatic conveying machine which is completely automatically driven by an internal combustion engine.
It is finally highly desirable to provide a new and improved automatic pneumatic conveying machine which encompasses all of the above features as integral components of the machine, or separate components remotely connected to the machine.